I was standing today in the dark toolshed. The sun was shining outside and through the crack at the top of the door there came a sunbeam. From where I stood that beam of light, with the specks of dust floating in it, was the most striking thing in the place. Everything else was almost pitch-black. I was seeing the beam, not seeing things by it.
Then I moved, so that the beam fell on my eyes. Instantly the whole previous picture vanished. I saw no toolshed, and (above all) no beam. Instead I saw, framed in the irregular cranny at the top of the door, green leaves moving on the branches of a tree outside and beyond that, ninety-odd million miles away, the sun. Looking along the beam, and looking at the beam are very different experiences
C. S. Lewis, "Meditation in a Toolshed"
For God, who said, "Let light shine out of darkness," has shone in our hearts to give the light of the knowledge of the glory of God in the face of Jesus Christ